This is an original U.S. utility patent application, and has no relation to previously filed U.S. or foreign patent applications, provisional applications, utility models, invention certificates, or registrations.
The present invention relates generally to the field of encoders and more particularly to rotation detecting encoders and mounting arrangements for modular rotation detecting encoders.
Modular encoder designs may be applied to both optical or magnetic encoders. It is thus pointed out that in the instant application, the term xe2x80x9cencoderxe2x80x9d may encompass various encoder forms in which a signal is transmitted through or reflected from a movable screen or temporary blockage to a sensor. Movement of the screen between unblocked and blocked areas affects the signal reception and the data (relating to the intensity, duration, or both intensity and duration of the signal with respect to the blocked and unblocked areas). The received signals may be used for many purposes.
In general, optical and magnetic encoders make use of a stationary sensor and rotating drum or disc. The sensor must be aligned and positioned with respect to the drum or disk for proper encoder operation.
Optical encoders are more widely used; therefore the examples illustrated and generally discussed herein will be directed at optical encoders. However, as noted above, this application should not be considered to be limited strictly to optical encoders.
The fundamental components of a known form of optical modular encoder include a disc with areas of clear and opaque sections, mounted to a hollow disc support fitting for attachment to a rotating shaft. A sensor is also provided, along with, a light source such as an LED, a mounting plate, a gapping and aligning assembly and mounting screws. The sensor and light source usually face each other on opposite sides of the disc.
As the disk rotates, the sensor detects light that passes through the rotating clear disc sections and will not detect light through opaque, blocked sections. Alternating states, between the clear and opaque sections, trigger electrical output signals that may be used to determine shaft position, speed, and direction.
It is desirable to set and establish a precise radial alignment and axial air gap between the disc and sensor. It is also desirable to provide for simplified yet accurate installation of an encoder, that will assure such alignment and spacing for proper encoder operation.